1. Technical Field
The present invention relates to a method and apparatus for locating an electrical short between two nets in an electrical wire network.
2. Related Art
Current technology is unable to accurately, efficiently, and nondestructively locate an electrical short between two nets in an electrical network of a microelectronic structure (e.g., a circuit board).
A method and apparatus is needed for accurately, efficiently, and nondestructively locating an electrical short between two nets in an electrical network of a microelectronic structure.
The present invention provides a method for locating a short between a first net and a second net, comprising the steps of:
providing the first net and the second net, wherein the second net is electrically shorted to the first net at an unknown point PS on the first net;
selecting points PA and PB on the first net such that PS is at a location on a path between PA and PB along the first net;
electrically connecting a constant current pulse source between PA and PB;
electrically connecting a first voltage measuring device between PA and PB;
selecting a point PC on the second net;
electrically connecting a second voltage measuring device between PA and PC;
activating the constant current pulse source to generate a constant current pulse at a time t=0, wherein the constant current pulse has a width xcfx84 and a height I;
activating the first voltage measuring device at a time t1, wherein 0 less than t1 less than xcfx84, and wherein the first voltage measuring device records a voltage drop VAB from PA to PB;
activating the second voltage measuring device at a time t2, wherein 0 less than t2 less than xcfx84, and wherein the second voltage measuring device records a voltage drop VAC from PA to PC;
defining LAS as a length of the path from PA to PS; and
calculating LAS as a function of VAC/VAB.
The present invention provides an apparatus for locating a short between a first net and a second net, comprising:
the first net and the second net, wherein the second net is electrically shorted to the first net at an unknown point PS on the first;
points PA and PB on the first net such that PS is at a location on a path between PA and PB along the first net;
a constant current pulse source electrically connected to PA and PB, wherein the constant current pulse source is generating a constant current pulse having a pulse width xcfx84 and pulse height I;
a first voltage measuring device electrically connected between PA and PB, wherein the first voltage measuring device is recording a voltage drop VAB from PA to PB; and
a second voltage measuring device electrically connected between PA and a point PC on the second net, wherein the second voltage measuring device is recording a voltage drop VAC from PA to PC; and
a calculation algorithm which computes LAS as a function of VAC/VAB, wherein LAS is a length of the path from PA to PS.
The present invention provides a computer method for locating a short between a first net and a second net such that the short is at a point PS at a location on a path between points PA and PB on the first net, comprising the steps of:
providing a computer system having:
a memory device;
a computer code located on the memory device, said computer code including a calculational algorithm which calculates a length LAS along the path from PA to PS;
a processor for executing the computer code; and
an output device;
providing input data for the computer code, including: a voltage drop VAB from PA to PB, a voltage drop VAC from PA to a point PC on the second net, and geometric data describing a spatial distribution of an electrical wire network which includes the first net;
executing the computer code, wherein the calculational algorithm computes a length LAS of the path from PA to PS as a function of VAC/VAB including utilizing the geometric data; and
displaying LAS by the output device.
The present invention provides a computer system for locating a short between a first net and a second net such that the short is at a point PS at a location on a path between points PA and PB on the first net, comprising:
a memory device;
input data stored for use by a computer code, said input data including: a voltage drop VAB from PA to PB, a voltage drop VAC from PA to a point PC on the second net, and geometric data describing a spatial distribution of an electrical wire network which includes the first net;
the computer code located on the memory device, wherein the computer code includes a calculation algorithm which utilizes VAC, VAB, and the geometric data to calculate a length LAS along the path from PA to PS as a function of VAC/VAB;
a processor which executes the computer code; and
an output device which receives output from the computer code, said output including output data selected from the group consisting of LAS, a graphical image displaying a location of the short, and a combination thereof.
The present invention provides a computer program product, comprising:
a computer usable medium having a computer readable program code embodied therein for locating a short between a first net and a second net such that the short is at a point PS at a location on a path between points PA and PB on the first net, wherein the computer readable program code includes:
a utilization of input data for locating the short, wherein the input date comprises: a voltage drop VAB from PA to PB, a voltage drop VAC from PA to a point PC on the second net, and geometric data describing a spatial distribution of an electrical wire network which includes the first net and the second net, and
a calculation of locational information selected from the group consisting of a length LAS along the path from PA to PS as a function of VAC/VAB, a graphical image displaying a location of the short, and a combination thereof.
The present invention provides a method, apparatus, and computer program product for accurately, efficiently, and nondestructively locating an electrical short between two nets in an electrical network of a microelectronic structure.